鲢幼鱼对不同气量气泡幕的趋避行为

Approach-Avoidance Behavior of Juvenile Silver Carp to a Bubble Curtain at Different Gas Flows

研究鲢幼鱼在静水且黑暗处理下对不同气量气泡幕的响应,并观察发现其中的逃避行为,探究其在应对不同气量气泡幕时的行为策略及响应关系,为过鱼设施诱驱鱼手段的利用提供依据。鲢幼鱼体重（14.62±1.84）g、体长（11.68±0.56）cm。试验装置为自制钢混结构水槽,水槽中间位置底部铺设PVC管,上侧顶端布置小孔。气量设置：对照组0,试验组10、20、30、40、60、80、100和120 L/min。每次试验结束后更换试验鱼进行下一次试验。观察记录试验鱼在气泡幕前的折返情况、尝试距离和逃逸方式。结果表明：（1）对照组通过率（100%）显著高于试验组（平均53%）,20、30 L/min时通过率最低,为40%;（2）对照组鲢幼鱼的尝试距离（229.6 cm）大于试验组的平均尝试距离（152.4 cm）,对照组与30 L/min组之间鲢幼鱼尝试距离差异显著（P〈0.05）,其他组间均无显著性差异（P〉0.05）,30 L/min气量组鲢幼鱼的尝试距离最小;（3）鲢幼鱼对气泡幕的通过率与尝试距离呈正相关,30 L/min工况下鲢幼鱼的通过率与尝试距离相对应,均为所有试验组中最小;（4）鲢幼鱼的逃逸次数占比随着气量的增大而增加。声场和水流流场的耦合作用对鱼趋避气泡幕行为的影响需要进一步研究。

Bubble curtains are a practical and inexpensive means of guiding fish movement.Studies have shown that the efficacy of bubble curtains is influenced by fish species,the shape of bubble curtain,arrangement pattern and environmental variables.In this study,silver carp were selected as the test fish and approach-avoidance behavior was observed toward bubble curtains with different gas flows.The behavioral strategies and responses of silver carp to bubble curtains of different densities was discussed.Juvenile silver carp of body weight（14.62 ± 1.84） g and length（11.68 ± 0.56） cm were acclimated for seven days before testing in aerated tap water at（20 ± 2） ℃,dissolved oxygen 〉7 mg/L and ammonia nitrogen 〈0.01 mg/L.The experiment was carried out in a steel-concrete basin（7 m × 0.8 m × 1.2 m）.The bubble curtain was generated using a PVC pipe with holes（diameter：1.5 mm） drilled（every 2.5 cm） along the top,centered at the bottom of the sink and connected to an air compressor.Eight gas flow（0,10,20,30,40,60,80 and 120 L/min） treatments were set and each treatment was repeated 10 times.One silver carp was selected for each trial and placed in the acclimation area,demarcated with a net,of the sink for 30 min.The test began by lifting the net and the time was recorded when the fish passed through the bubble curtain.The trial ended when the fish passed through the curtain,or after 60 minutes if the fish did not pass through the bubble curtain.Test fish were used only once and all trials were recorded with a video camera for analysis of test fish behavior in response to the bubble curtain.The behaviors noted included the time to pass,the longest distance of approach to the bubble curtain,avoidance and escape（passive or active）.There were four primary findings：（1） The passing rate of silver carp through the bubble curtain in the control group（100%）was significantly higher than the average passing rate（53%） of the different gas flow treatments.The passing rate of silver carp initially decreased and then increased with increasing gas flow,and the minimum passing rate occurred in the gas flow treatments of 20,30 L/min.（2） The longest attempt distance（in approaching the bubble curtain） in the control group（229.6 cm） was also higher than the average attempt distance（152.4 cm） of the different gas flow treatments,with significant difference between the control group and the gas flow treatment of 30 L/min（P 〈0.05）.（3） The attempt distance initially decreased and then increased with increasing gas flow,and the passing rate was positively correlated with the attempt distance.（4） With increasing gas flow,the juvenile silver carp showed more escape behavior,resulting from the stronger stimulus,when approaching the bubble curtain.When the gas flow reached 40 L/min,the silver carp escaped passively.The results provide technical support for repelling fish without injury and a reference for attracting or repelling fish in the design of fish passage facilities.